Odontogenic Carcinosarcoma of the Mandible, a Case Report

Odontogenic carcinosarcoma is an extremely rare malignant mixed odontogenic tumor, in which both epithelial and mesenchymal component showing malignant cytology features. Due to paucity of reported cases, clinical appearance is unclear. Present study reports a mandibular odontogenic carcinosarcoma in a 33 years-old male with a history of painless mass in the anterior of mandible. The histopathological examination demonstrated a biphasic malignant neoplasm with both epithelial and mesenchymal component malignant features. There were follicles and strands of odontogenic epithelium, which were lined peripherally by ameloblast-like cells. Mesenchyme of tumor was highly cellular resembling dental papilla. Partial mandibular resection, consisting wide surgical excision with immediate reconstruction was accomplished.


Introduction
Malignant odontogenic tumors are rare groups of malignant cancers, which arise from remnants of odontogenic epithelium [1]. One of these tumors is odontogenic carcinosarcoma (OCS), an extremely rare malignant odontogenic tumor in which both the epithelial and the ectomesenchymal components demonstrate malignant features cytologically [2][3][4][5][6].
There are few published case reports of OCS in the literature and they were not specified in WHO classification until 1992 [7]. Therefore, its clinical appearance is unclear. However the review of literature demonstrates that these rarely malignant cases have exhibited aggressive clinical behavior [8][9].
OCS is related with some tumors which comprise of lesions that range from benign epithelial tumors such as ameloblastoma and ameloblastic fibroma to malignant tumors with metastatic potential like ameloblastic fibrosarcoma [9,10], but due to the scarcity of reported cases, this transformation remains unexplored. There are only twelve OCS cases in the English literature [7][8].
In this report, we describe a case which will be the thirteenth case of OCS arising from an ameloblastic fibroma in the mandible of 33 years-old male patient.

Discussion
Malignant odontogenic tumors have exceedingly rare incidence but nonetheless they occur [2]. Odontogenic malignancies have different origins. Some arise from odontogenic epithelial remnants, residues from embryologic odontogenesis process. Others may develop from preexisting lesions. The mechanism of these transformations is not thoroughly elucidated [10].
As has been demonstrated, the proceeding of odontogenesis involves inductive interaction between the enamel organ and the ectomesenchyme of dental papilla.
It seems that similar induction can cause malignant odontogenic neoplasms like the process occurring in odontogenesis [11]. were considered as de novo [10][11], and other cases were occurred because of previous surgery or were arisen from a preexisting lesion [12] (Table 1).
Chikosi et al. [6] demonstrated the OCS which has been upraised from ameloblastoma and the OCS that has been reported by DeLair et al. [5] was originated from an ameloblastic fibroma. The cases, which have been reported by Kunkel et al. [4], were developed from ameloblastic fibrosarcoma.
Although the mechanism of malignant transformation from the benign previous odontogenic lesion is relative unknown, but it is reported that surgical trauma, multiple surgical resection, and radiotherapy seem to have important role in deriving reported cases [13].
In the English literature, there was a male predilecti-on and two cases presented in maxilla [14]. It is notable that odontogenic carcinosarcoma occurs more commonly in the posterior of mandible, but our case has been existed from anterior part of mandible [15].
Most of the cases are treated by surgical resection.
Some studies revealed that less aggressive resection cause an increase in the possibility of recurrence [14]. In our case, partial mandibular resection with wide surgical excision was performed and the patient is currently being followed up.

Conclusion
This is a case report of odontogenic carcinosarcoma with mixed features of both carcinomatous and sarcomatous components on histopathological evaluation. In spite of limited information about the clinical behavior of OCS, these tumors are very aggressive with high rates of recurrence and metastasis. However, partial resection of mandible seems to be the best treatment, considering the poor outcome of the lesion.